3GPP (Third Generation Partnership Project) discusses a standardization of mobile communication schemes. For example, high-speed wireless communication schemes such as LTE (Long Term Evolution) are standardized in 3GPP. In 3GPP release 12, D2D (device-to-device) communication was discussed as a new wireless communication scheme. Note that D2D communication is an LTE extended specification and may be referred to as LTE Device to Device Proximity Services.
In D2D communication, a wireless device can directly communicate with another wireless device without going via a base station. Thus, D2D communication is expected to provide small-delay communications. In addition, D2D communication can be performed even in an area where radio waves from a base station do not reach (or an area where a base station does not exist). Note that a communication link configured between wireless devices for D2D communication may be referred to as a D2D link in the following description.
D2D communication may be implemented by using a cellular communication system. That is, D2D communication may use resources of the cellular communication system (such as an LTE system). When a plurality of D2D links are configured, the same resource (for example, radio frequency or time slot) may be allocated to the plurality of D2D links. Accordingly, it is important to efficiently allocate resources for D2D links in a cellular communication system.
Note that a method and device for enabling D2D communications with signal structures that require minimal changes to the current LTE architecture is described in US Patent Publication No. 2015/0049732. In addition, International Publication Pamphlet No. WO2015/076867 describes a method of performing D2D data channel signaling.
However, in the conventional scheme, it is difficult to efficiently allocate resources for a D2D link in a cellular communication system while avoiding or suppressing interference from the cellular communication system to the D2D link.